0:00The most famous definition of a “species”
was proposed by the biologist Ernst Mayr
0:04back in the mid-1900s: species are groups
of interbreeding natural populations that
0:08for one reason or another, don’t have babies
with each other. But it turns out to be super
0:13hard to determine whether groups are actually
reproductively isolated, so other folks have
0:16tried to define what a species is based on looks,
or genetic similarity, or evolutionary history,
0:22or… well, it keeps going. These days, scientists
across different fields regularly use more than a
0:27dozen different so-called “species concepts”.
See, there’s a huge scientific debate about
0:32whether the red wolf is just a hybrid between
a coyote and a gray wolf, or whether it’s
0:36actually its own separately-evolving
species, OR maybe it used to be its
0:39own thing but that thing went extinct and
the current thing is actually a new hybrid?
0:43And that doesn’t even get into how
weird plants are about this stuff. Like,
0:46some plants can literally double their genome
when they reproduce – creating a totally new
0:51species in a single generation – which wreaks
all sorts of havoc on any attempts to clearly
0:55differentiate between species. So it is
really difficult to define a species.
